From: Eugeniu Rosca <erosca@de.adit-jv.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: <linux-usb@vger.kernel.org>, <linux-renesas-soc@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
"Lee, Chiasheng" <chiasheng.lee@intel.com>,
Mathieu Malaterre <malat@debian.org>,
Kai-Heng Feng <kai.heng.feng@canonical.com>,
Hardik Gajjar <hgajjar@de.adit-jv.com>, <scan-admin@coverity.com>,
Eugeniu Rosca <erosca@de.adit-jv.com>,
Eugeniu Rosca <roscaeugeniu@gmail.com>
Subject: Re: [PATCH] usb: hub: Fix unhandled return value of usb_autopm_get_interface()
Date: Tue, 25 Feb 2020 20:12:41 +0100 [thread overview]
Message-ID: <20200225191241.GA32410@lxhi-065.adit-jv.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.2002251028030.1485-100000@iolanthe.rowland.org>
Hi Alan,
Many thanks for the prompt review.
On Tue, Feb 25, 2020 at 10:32:32AM -0500, Alan Stern wrote:
> On Tue, 25 Feb 2020, Eugeniu Rosca wrote:
> > + int r = usb_autopm_get_interface(intf);
> > +
> > + if (!r)
> > + hub->quirk_disable_autosuspend = 1;
> > + else
> > + dev_dbg(&intf->dev, "disable autosuspend err=%d\n", r);
> > }
> >
> > if (hub_configure(hub, &desc->endpoint[0].desc) >= 0)
>
> This change is not necessary, because the resume operation cannot fail
> at this point (interfaces are always powered-up during probe).
Agreed to avoid unneeded complexity.
> A better solution would be to call usb_autpm_get_interface_no_resume()
> instead.
Pushed to https://lore.kernel.org/lkml/20200225183057.31953-1-erosca@de.adit-jv.com
>
> On the other hand, the other places that call
> usb_autopm_get_interface() without checking should be audited. Some of
> them almost certainly need to be fixed.
A quick 'git grep' outputs below list of auditable candidates [1].
With no relevant devices at hand, I would avoid touching these drivers,
since oftentimes even legitimate patches introduce regressions w/o
testing.
If anybody volunteers with testing, I guess it should be quick to
either convert usb_autpm_get_interface to *_no_resume variant or
handle the return value in place in below instances.
[1] (v5.6-rc3) git grep -En "[^=]\s+usb_autopm_get_interface\("
drivers/input/touchscreen/usbtouchscreen.c:1788: usb_autopm_get_interface(intf);
drivers/media/usb/stkwebcam/stk-webcam.c:628: usb_autopm_get_interface(dev->interface);
drivers/net/usb/hso.c:1308: usb_autopm_get_interface(serial->parent->interface);
drivers/net/usb/r8152.c:5231: usb_autopm_get_interface(tp->intf);
sound/usb/usx2y/us122l.c:192: usb_autopm_get_interface(iface);
--
Best Regards
Eugeniu Rosca
next prev parent reply other threads:[~2020-02-25 19:12 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 13:08 [PATCH] usb: hub: Fix unhandled return value of usb_autopm_get_interface() Eugeniu Rosca
2020-02-25 15:32 ` Alan Stern
2020-02-25 19:12 ` Eugeniu Rosca [this message]
2020-02-25 19:39 ` Alan Stern
2020-02-25 20:22 ` Eugeniu Rosca
2020-02-25 20:54 ` Alan Stern
2020-02-26 18:10 ` Eugeniu Rosca
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